In Kellen Mond's first practice back from a 10-day stint on the COVID-19 reserve list, the rookie quarterback looked "rusty," coach Mike Zimmer said. And Mond's first appearance in a preseason game, it appears, will have to wait.

Zimmer said the third-round pick won't play in the Vikings' preseason opener against the Broncos on Saturday, indicating Mond's work in two days of joint practices against Denver would be his only time facing another team this week. Mond, who tested positive for COVID-19 on July 31, took part in virtual meetings during his time away, but his lack of on-field work showed up in a Tuesday practice the Vikings converted to a walk-through.

"It's 10 days out. He's catching up," Zimmer said. "He was good with all the things. He was a little slow with his reads, I thought. We had the 2-minute drill, and he was kind of, and I know it was just kind of a walk-through thing, but he needs to speed up the tempo a little bit."

The Vikings are likely to play without both of their top two picks on Saturday night; first-rounder Christian Darrisaw hasn't practiced following pre-draft surgery on a groin injury and the offensive tackle is "probably out" on Saturday, Zimmer said, while Mond will wait at least a week to make his preseason debut.

His absence means the Vikings would have four quarterbacks available to them on Saturday: Kirk Cousins, Jake Browning, Nate Stanley and Danny Etling, who joined the team last week.

Zimmer would not say how much the Vikings' starters will play on Saturday, though Cousins — who played nine snaps in both of his preseason openers with the Vikings, going 4-for-4 with a TD pass in each game — said he wanted to play as much as the coaches will let him.

"I think we're always going to get better from the reps, and so it's hard to not to want to be in there and learning," Cousins said. "Even if you're making mistakes, you're making them in a time when it's not going to hurt you. So you'd rather go out there and make the mistakes in August than make them in September. It's up to the coaches to make those decisions on how much to balance that."